We will develop a system consisting of instrumentation, reagents and methods for rapid whole cell nuclear reporter assays for high throughput screening (HTS) of lead compounds in drug discovery applications. The approach is based on the use of green fluorescent proteins as an intracellular market, and fluorescence lifetime sensing to quantify reporter gene expression. A key innovation of the approach is the use of a new fluorescence lifetime sensing technology, recently developed by Ciencia which can be implemented in rugged, low-cost, compact instrumentation, and which is capable of high sensitivity, high lifetime resolution, and rapid measurement time. The proposed lifetime sensing approach will solve some fundamental problems of current intensity-based fluorescence system, such as artifacts due to photobleaching and non- specific cell autofluorescence background, and interference from colored compounds in the sample matrix. the long-term objective is to develop compact, robust, sensitive, low-cost instrumentation and assays for high throughput screening in drug discovery. the proposed work addresses the needs of pharmaceutical companies which are under competitive pressures to bring successful new therapeutic products to market faster and more efficiently. To our knowledge, this would be the first time that fluorescence lifetime sensing is exploited for high throughput screening applications. PROPOSED COMMERCIAL APPLICATION: High throughput screening in lead drug discovery, cell and molecular biology research instrumentation, clinical diagnostics, agriculture, food processing , environmental analysis forensics.